Brain Disruptions Weaken Self-Control In Chronic Dieters

Many people fall prey to the vicious cycle of chronic dieting. Oftentimes willpower waxes and wanes leading to limited dieting success. A new study from Dartmouth using neuroimaging suggests that a brain imbalance may be responsible for overeating in chronic dieters. This imbalance occurs when the region that controls impulse behavior and self-control becomes disrupted, which decreases the ability to resist temptation.

This study indicates that dieters may have more success if they avoid tempting situations that challenge their self-control.

These new results bring more understanding to the brain mechanism of many impulse behaviors such as obesity and substance abuse. Professor Todd Heatherton explained that the team has two future research paths. The first method would be to investigate if self-control can be strengthened over time, similarly to how muscles are strengthened by exercise and rest, by routinely subjecting participants to minor temptations. Another option is to study the connection between brain processes and social behavior.

Previous studies have shown that people possess a limited supply of willpower and this amount diminishes as it is used to cope with stress, temptation and other situations requiring willpower. When the supply of self-control is low, people are left vulnerable to impulsive and undesirable behavior. In 2011, a study from Dartmouth indicated that willpower fails as the impulse strength exceeds a person’s capacity to regulate it.

This current study was composed of 31 women participants who were chronic dieters. First, they completed an attention-control task designed to not deplete their self-control reserves. Afterwards, they were shown images of appetizing high calorie food while undergoing a functional magnetic resonance imaging test (fMRI). The results showed that in the orbitofrontal cortex, a brain area related to food rewards, there was greater activity in depleted dieters. Also there was a reduced amount of connectivity between that area and a region used for self-control known as the inferior frontal gyrus.

These research discoveries suggest that depleting a person’s reserves diminishes the ability to exercise self-control by lessening brain connections between cognitive control areas and reward areas, which lowers the ability to resist temptations.